The objective of this work is to elucidate mechanisms involved in the regulation of viral gene transcription. The first major emphasis is on adenovirus genes which encode the VA RNAs and on cellular genes which encode the 5S and tRNAs. Purified or cloned DNAs containing these genes have been shown to be accurately transcribed by purified (host) class III RNA polymerases in the presence of other factors isolated from uninfected cells. In future studies we will (1) attempt to complete the purification of the factors necessary for the transcription of the purified genes by the purified RNA polymerases; (2) determine whether they are the same for different cellular and viral genes transcribed by RNA polymerase III; (3) determine whether these factors are sufficient to activate the same genes in standard viral nucleoprotein or cellular chromatin structures and, if not, (4) search for other cellular or viral induced transcription factors which act in conjunction with these factors, and which will restore the regulation of these genes observed in vivo; (5) investigate the mechanism(s) of action of the various transcription components in terms of sequence specific binding to DNA, the induction of chromatin structural modifications, etc. The second major emphasis will be on those viral genes which encode mRNAs and which we have recently shown can also be accurately transcribed by RNA polymerase II and other factors in a reconstituted cell-free system. We will continue to focus on the major late transcription unit, to which our analyses have thus far been restricted, and will investigate this system as outlined for the class III genes. We will concomitantly initiate similar studies of the adenovirus early genes.